Uplink power control for srs carrier-based switching

ABSTRACT

According to some embodiments, a method for use in a user equipment (UE) operable to transmit a sounding reference signal (SRS) on a plurality of carriers comprises: obtaining an indication to perform SRS carrier-based switching for a carrier; adapting a parameter for uplink transmit power control in response to the obtained indication; and transmitting an uplink signal using the adapted parameter while meeting at least one predetermined uplink power control requirement. According to some embodiments, a method for use in a network node operable to receive a SRS on a plurality of carriers comprises: sending, to a UE, an indication to perform SRS carrier-based switching for a carrier; and receiving, from the UE, an uplink signal based on the parameter for uplink transmit power control adapted in response to the sent indication, wherein the uplink signal meets at least one uplink power control requirement.

This application is a continuation of U.S. patent application Ser. No.17/212,501, filed Mar. 25, 2021, which is a continuation of U.S. patentapplication Ser. No. 16/097,190, filed Oct. 26, 2018, now U.S. Pat. No.10,986,582, which is a 35 U.S.C. § 371 national phase filing ofInternational Application No. PCT/IB2017/052802, filed May 12, 2017,which claims priority to U.S. Provisional Application No. 62/336,357,filed May 13, 2016, the disclosures of which are incorporated herein byreference in their entireties.

TECHNICAL FIELD

Particular embodiments are directed to wireless communications and, moreparticularly, to methods and apparatus for assuring uplink power controlaccuracy during sounding reference signal (SRS) carrier-based switching.

INTRODUCTION

Third Generation Partnership Project (3GPP) long term evolution (LTE)wireless networks may use sounding reference signals (SRS). SRS areknown signals that are transmitted by a user equipment (UE) so that aneNodeB can estimate different uplink-channel properties. The estimatesmay be used for uplink scheduling, link adaptation, and also fordownlink multiple antenna transmission, particularly for time divisionduplex (TDD) networks where the uplink and downlink use the samefrequencies. An example is illustrated in FIG. 1.

FIG. 1 illustrates an example radio subframe with SRS. The horizontalaxis represents time and the other axis represents frequency. In theillustrated example, subframe 10 includes 14 orthogonal frequencydivision multiplexed (OFDM) symbols (illustrated as columns). SRS 16 ishas a time duration of a single OFDM symbol.

A UE may transmit SRS transmitted in the last symbol of a 1 ms uplinksubframe. For TDD, the UE may transmit the SRS in the special slotUpPTS. The length of UpPTS can be configured to be one or two symbols.An example is illustrated in FIG. 2.

FIG. 2 illustrates an example subframe format for TDD. The illustratedexample includes one 10 ms radio frame for TDD divided into threedownlink transmissions and two uplink transmissions. Up to eight symbolsmay be set aside for SRS. As illustrated, the special subframe UpPTSwindow may include up to two SRS, and the last symbol of each uplinksubframe may also include an SRS.

The configuration of SRS symbols, such as SRS bandwidth, SRS frequencydomain position, SRS hopping pattern, and SRS subframe configuration areset semi-statically as a part of a radio resource control (RRC)information element (IE).

LTE uplink includes two types of SRS transmission—periodic and aperiodicSRS transmission. A UE transmits periodic SRS at regular time instancesas configured by RRC signaling. Aperiodic SRS is a one shot transmissionthat is triggered by signaling in a physical downlink control channel(PDCCH).

SRS configuration includes cell specific SRS configuration and UEspecific configuration. Cell specific configuration indicates whichsubframes that a UE may use for SRS transmissions within the cell, asillustrated in FIG. 2 above.

UE specific configuration indicates to the UE a pattern of subframes(among the subframes reserved for SRS transmission within the cell) andfrequency domain resources to that the specific UE may use for SRStransmission. It also includes other parameters that the UE may use whentransmitting the signal, such as frequency domain comb and cyclic shift.

SRS from different UEs can be multiplexed in the time domain by usingUE-specific configurations such that the SRS of the two UEs aretransmitted in different subframes. Furthermore, within the same symbol,SRS can be multiplexed in the frequency domain. The set of subcarriersis divided into two sets of subcarriers (or combs) with the even and oddsubcarriers, respectively, in each such set. Additionally, UEs may havedifferent bandwidths to get additional frequency division multiplexing(FDM). The comb enables frequency domain multiplexing of signals withdifferent bandwidths and also overlapping. Code division multiplexing(CDM) may also be used. Using CDM, UEs can use the same time andfrequency domain resources by using different shifts of a basic basesequence.

LTE networks may support carrier aggregation (CA). Many networks maycarry traffic that is downlink-heavy, which results in a greater numberof aggregated downlink component carriers (CC) than the number of(aggregated) uplink CCs. For existing UE categories, a typical CAcapable UE only supports one or two uplink CCs.

For the carrier supporting both uplink and downlink, transmit diversitybased feedback without precoding matrix indicator (PMI) and with SRS isbeneficial because channel reciprocity can be used. However, a UEgenerally has the capability of aggregating a larger number of downlinkcarriers than uplink carriers. As a result, some of the TDD carrierswith downlink transmission for the UE will not have an uplinktransmission that includes SRS. Channel reciprocity cannot be used forthese carriers. Such situations will become more severe with CAenhancement of up to 32 CCs where a large portion of CCs are TDD.Allowing fast carrier switching to and between TDD uplink carriers canbe a solution to allow SRS transmission on these TDD carriers and shouldbe supported.

SRS based carrier switching supports SRS switching to and between TDDcomponent carrier(s). SRS based carrier switching is used where thecomponent carriers available for SRS transmission correspond to thecomponent carriers available for carrier aggregation of physicaldownlink shared channel (PDSCH), while the UE has fewer componentcarriers available for carrier aggregation of physical uplink sharedchannel (PUSCH).

3GPP TS 36.101 V13.3.0 (2016-03) defines absolute and relative powertolerance to control the uplink transmit power quality. Absolute powertolerance is the ability of a UE transmitter to set its initial outputpower to a specific value for the first sub-frame at the start of acontiguous transmission or non-contiguous transmission with atransmission gap larger than 20 ms. In the case of a physical randomaccess channel (PRACH) transmission, the absolute tolerance is specifiedfor the first preamble. The absolute power tolerance includes thechannel estimation error (the absolute reference signal received power(RSRP) accuracy requirement specified in subclause 9.1 of 3GPP TS36.133). The absolute power tolerance is ±9.0 dB in normal conditionsand ±12.0 dB in extreme conditions and applies over the power rangebounded by the maximum output power and the minimum output power.

The relative power tolerance is the ability of the UE transmitter to setits output power in a target sub-frame relatively to the power of themost recently transmitted reference sub-frame if the transmission gapbetween these sub-frames is ≤20 ms. For PRACH transmission, the relativetolerance is the ability of the UE transmitter to set its output powerrelatively to the power of the most recently transmitted preamble, wherethe measurement period for the PRACH preamble is pre-defined and is asbelow.

TABLE 1 PRACH ON power measurement period (TS 36.101, Table 6.3.4.2-1)PRACH Measurement preamble period format (ms) 0 0.9031 1 1.4844 2 1.80313 2.2844 4 0.1479

The relative transmit power tolerance depends on power step (which isset by a transmit power control (TPC) command and/or an uplinkscheduling grant), a set of transmitted channels in the subframe, andconditions (normal or extreme).

TABLE 2 Relative power tolerance for transmission (normal conditions)(TS 36.101, Table 6.3.5.2.1-1) All combinations of All PUSCH/PUCCHcombinations of and SRS Power step PUSCH and transitions ΔP (Up or PUCCHbetween sub- PRACH down) [dB] transitions [dB] frames [dB] [dB] ΔP < 2±2.5 ±3.0 ±2.5 (NOTE 3) 2 ≤ ΔP < 3 ±3.0 ±4.0 ±3.0 3 ≤ ΔP < 4 ±3.5 ±5.0±3.5 4 ≤ ΔP ≤ 10 ±4.0 ±6.0 ±4.0 10 ≤ ΔP < 15 ±5.0 ±8.0 ±5.0 15 ≤ ΔP ±6.0±9.0 ±6.0 NOTE 1: For extreme conditions an additional ± 2.0 dBrelaxation is allowed NOTE 2: For operating bands under NOTE 2 in Table6.2.2-1, the relative power tolerance is relaxed by increasing the upperlimit by 1.5 dB if the transmission bandwidth of the referencesub-frames is confined within F_(UL)_low and F_(UL)_low + 4 MHz orF_(UL)_high − 4 MHz and F_(UL)_high and the target sub-frame is notconfined within any one of these frequency ranges; if the transmissionbandwidth of the target sub-frame is confined within F_(UL)_low andF_(UL)_low + 4 MHz or F_(UL)_high − 4 MHz and F_(UL)_high and thereference sub-frame is not confined within any one of these frequencyranges, then the tolerance is relaxed by reducing the lower limit by 1.5dB. NOTE 3: For PUSCH to PUSCH transitions with the allocated resourceblocks fixed in frequency and no transmission gaps other than thosegenerated by downlink subframes, DwPTS fields or Guard Periods for TDD:for a power step ΔP ≤ 1 dB, the relative power tolerance fortransmission is ± 1.0 dB.

Aggregate power control tolerance is the ability of a UE to maintain itspower in non-contiguous transmission within 21 ms in response to 0 dBTPC commands with respect to the first UE transmission (provided thatthe power control parameters remain unchanged). The minimum requirementfor the aggregate power control tolerance is ±2.5 dB for PUCCH and ±3.5dB for PUSCH, assuming UE transmission gap of 4 ms and that the transmitpower control command is transmitted via PDCCH 4 subframes precedingeach PUCCH and PUSCH transmission, respectively.

TS 36.101 also specifies transmit power control tolerance (absolute,relative, and aggregate) with CA, in a similar way as described fornon-CA above. The requirements apply for one single PUCCH, PUSCH or SRStransmission of contiguous physical resource block (PRB) allocation perCC for all CCs with all component carriers active. The requirements canbe tested by time aligning any transmission gaps on all the componentcarriers.

LTE may also operate in unlicensed spectrum. Some of these operationsare described below.

One mode is referred to as licensed-assisted access (LAA) to unlicensedspectrum using LTE. The unlicensed spectrum (e.g., in 5-6 GHz range suchbetween: 5150 MHz-5925 MHz) can be simultaneously used by multipledifferent technologies (e.g., between LTE and IEEE Wi-Fi). LAAfacilitates LTE equipment to operate in an unlicensed radio spectrum.The same LAA concept can be used in other spectrum (i.e., 3.5 GHz inNorth America) as well. An example is illustrated in FIG. 3.

FIG. 3 illustrates a UE operating in LAA mode in an LTE network. In LAAmode, devices connect in the licensed spectrum (primary cell or PCell)and use carrier aggregation to benefit from additional transmissioncapacity in the unlicensed spectrum (secondary cell or SCell).Therefore, a UE can be configured with one or more SCells in theunlicensed spectrum, which are operated with frame structure type 3.

Because the unlicensed spectrum must be shared with other wirelesstechnologies (e.g., Wi-Fi, radar, Bluetooth, fixed satellite system,etc.), a listen-before-talk (LBT) method is used. LBT involves sensingthe medium for a pre-defined minimum amount of time to determine whetherthere is a transmission, and backing off if the channel is busy (i.e.,not transmitting if there is a transmission on the channel).

Some LTE systems operate in unlicensed spectrum completely in astandalone manner. The difference between LAA and standalone LTE inunlicensed band is that standalone usage does not include a licensedcarrier to be aggregated with unlicensed carrier, while an unlicensedLTE carrier is always aggregated with a licensed carrier in LAAoperations. Standalone operation means that uplink is allowed inunlicensed spectrum. Because support from a licensed carrier is notavailable, the standalone LTE system is responsible for allfunctionalities in unlicensed spectrum.

LAA may also operate in dual connectivity (DC) mode. The unlicensedcarrier can be aggregated with a licensed carrier using dualconnectivity. In dual connectivity mode, at least one CC in MeNB istermed as PCell and at least one CC in SeNB is termed as PSCell. PCelland PSCell are functionally similar nodes. However activation,deactivation, configuration, deconfiguration of PSCell is controlled bythe PCell. The connected nodes in DC operation are independent to eachother, thus, all control signaling is done separately.

LTE also includes license-shared operation. In a licensed sharedspectrum, more than one radio access technology (RAT) has permission toaccess the spectrum. All the RATs have equal status in terms ofpriority. The allowed systems access the spectrum based on a fairnesscriterion, e.g. LBT. This is also referred to as horizontal sharing ofthe spectrum. LTE may be used in such spectrum scenarios.

Particular problems exist with SRS carrier-based switching. Usingcurrent uplink power accuracy requirements, the SRS transmission may notobtain the power control accuracy when SRS carrier-based switching isused. This depends on the transmission gap in time between two uplinktransmissions in any carrier. If the transmission gap is larger than acertain value, then the UE has to meet absolute tolerance requirementfor uplink power control. Otherwise, the UE has to meet relativetolerance requirement for the uplink power control.

For SRS carrier-based switching, this can be a problem, because (1)there may not be any uplink transmission in the carrier within the gaptime; and (2) there may be a number of SRS carrier-based switchingoperations planned which may increase the gap time. In addition, uplinkand/or downlink LBT will also increase the gap when uplink and/ordownlink LBT is required in at least one carrier where SRS carrier-basedswitching is performed.

SUMMARY

The embodiments described herein include adapting uplink power controlparameters for sounding reference signals (SRS) carrier-based switching.According to some embodiments, a method for use in a user equipment (UE)operable to transmit a SRS on a plurality of carriers comprises:obtaining an indication to perform SRS carrier-based switching for atleast one carrier of the plurality of carriers; adapting at least oneparameter for uplink transmit power control in response to the obtainedindication; and transmitting an uplink signal using the adapted at leastone parameter for uplink power control while meeting at least onepredetermined uplink power control requirement.

In particular embodiments, adapting the at least one parameter foruplink transmit power control comprises adapting a transmission gapparameter. Meeting at least one predetermined uplink power controlrequirement comprises meeting at least one absolute power controlrequirement or meeting at least one relative power control requirementbased on the transmission gap parameter. For example, adapting thetransmission gap parameter may comprise adapting the transmission gapparameter to 40 ms. Meeting at least one predetermined uplink powercontrol requirement may comprise meeting at least one absolute powercontrol requirement when the transmission gap length is greater than 40ms and meeting at least one relative power control requirement when thetransmission gap length is less than or equal to 40 ms.

In particular embodiments, adapting the transmission gap parametercomprises adapting at least one of an uplink power control step powervalue, an uplink power control step time value, an absolute transmitpower, and a relative transmit power. Meeting at least one predetermineduplink power control requirement may comprise meeting at least one of anabsolute transmit power tolerance, an aggregate power controlrequirement, an uplink power control accuracy requirement, and minimumor maximum transmit power adjustment over a single step or period oftime.

In particular embodiments, the method further comprises obtaining anindication that a listen-before-talk (LBT) procedure is used in theuplink or downlink. Adapting the at least one parameter for uplinktransmit power control may be based on the indication that the LBTprocedure is used in the uplink or downlink. The indication that a LBTprocedure is used in the uplink or downlink may apply to a particularcarrier of the plurality of carriers. Adapting the at least oneparameter for uplink transmit power control may be based on whether thecarrier for SRS carrier-based switching is the same carrier as theindicated particular LBT carrier.

According to some embodiments, a method for use in a network nodeoperable to receive a SRS on a plurality of carriers comprises: sending,to a UE, an indication to perform SRS carrier-based switching for atleast one carrier of the plurality of carriers; and receiving, from theUE, an uplink signal based on at least one parameter for uplink transmitpower control adapted in response to the sent indication, wherein theuplink signal meets at least one uplink power control requirement.

In particular embodiments, the at least one parameter for uplinktransmit power control adapted in response to the sent indicationcomprises a transmission gap parameter. The at least one uplink powercontrol requirement comprises meeting at least one absolute powercontrol requirement or meeting at least one relative power controlrequirement based on the transmission gap parameter. For example, the atleast one parameter for uplink transmit power control adapted inresponse to the sent indication may comprise a transmission gapparameter adapted to 40 ms. The at least one uplink power controlrequirement may comprise meeting at least one absolute power controlrequirement when the transmission gap length is greater than 40 ms andmeeting at least one relative power control requirement when thetransmission gap length is less than or equal to 40 ms.

In particular embodiments, the at least one parameter for uplinktransmit power control adapted in response to the sent indicationcomprises at least one of an uplink power control step power value, anuplink power control step time value, an absolute transmit power, and arelative transmit power. The at least one uplink power controlrequirement may comprise meeting at least one of an absolute transmitpower tolerance, an aggregate power control requirement, an uplink powercontrol accuracy requirement, and minimum or maximum transmit poweradjustment over a single step or period of time.

In particular embodiments, the method further comprises sending, to theUE, the at least one parameter for uplink transmit power control. The atleast one parameter for uplink transmit power control may comprise atransmission gap parameter.

In particular embodiments, the adapted at least one parameter for uplinktransmit power control is adapted based on whether a LBT procedure isused in the uplink or downlink.

According to some embodiments, a UE operable to transmit a SRS on aplurality of carriers comprises a memory coupled to a processor. Theprocessor is operable to: obtain an indication to perform SRScarrier-based switching for at least one carrier of the plurality ofcarriers; adapt at least one parameter for uplink transmit power controlin response to the obtained indication; and transmit an uplink signalusing the adapted at least one parameter for uplink power control whilemeeting at least one predetermined uplink power control requirement.

According to some embodiments, a network node operable to receive a SRSon a plurality of carriers comprises a memory coupled to a processor.The processor is operable to: send, to a UE, an indication to performSRS carrier-based switching for at least one carrier of the plurality ofcarriers; and receive, from the UE, an uplink signal based on at leastone parameter for uplink transmit power control adapted in response tothe sent indication, wherein the uplink signal meets at least one uplinkpower control requirement.

According to some embodiments, a UE operable to transmit a SRS on aplurality of carriers comprises an obtaining module, an adapting module,and a transmitting module. The obtaining module is operable to obtain anindication to perform SRS carrier-based switching for at least onecarrier of the plurality of carriers. The adapting module is operable toadapt at least one parameter for uplink transmit power control inresponse to the obtained indication. The transmitting module is operableto transmit an uplink signal using the adapted at least one parameterfor uplink power control while meeting at least one predetermined uplinkpower control requirement.

According to some embodiments, a network node operable to receive a SRSon a plurality of carriers comprises a sending module and a receivingmodule. The sending module is operable to send, to a UE, an indicationto perform SRS carrier-based switching for at least one carrier of theplurality of carriers. The receiving module is operable to receive, fromthe UE, an uplink signal based on at least one parameter for uplinktransmit power control adapted in response to the sent indication,wherein the uplink signal meets at least one uplink power controlrequirement.

Also disclosed is a computer program product. The computer programproduct comprises instructions stored on non-transient computer-readablemedia which, when executed by a processor, perform the acts of obtainingan indication to perform SRS carrier-based switching for at least onecarrier of the plurality of carriers; adapting at least one parameterfor uplink transmit power control in response to the obtainedindication; and transmitting an uplink signal using the adapted at leastone parameter for uplink power control while meeting at least onepredetermined uplink power control requirement.

Another computer program product comprises instructions stored onnon-transient computer-readable media which, when executed by aprocessor, perform the acts of sending, to a UE, an indication toperform SRS carrier-based switching for at least one carrier of theplurality of carriers; and receiving, from the UE, an uplink signalbased on at least one parameter for uplink transmit power controladapted in response to the sent indication, wherein the uplink signalmeets at least one uplink power control requirement.

Particular embodiments may exhibit some of the following technicaladvantages. For example, particular embodiments may enhance uplink powercontrol performance when SRS carrier-based switching is performed. TheUE behavior for uplink power control under SRS switching is welldefined. This enables the network to configure the UE with uplinksignals that the UE can transmit with optimal power. Particularembodiments include flexibility to obtain uplink power control accuracyrequirements when SRS carrier-based switching is used for both licensedand unlicensed spectrum. Some embodiments provide adaptationpossibilities to SRS transmissions for different carriers when SRScarrier-based switching is used involving licensed spectrum orunlicensed spectrum or both. Other technical advantages will be readilyapparent to one skilled in the art from the following figures,description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the embodiments and their featuresand advantages, reference is now made to the following description,taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates an example radio subframe with SRS;

FIG. 2 illustrates an example subframe format for TDD;

FIG. 3 illustrates a UE operating in LAA mode in an LTE network;

FIG. 4 is a block diagram illustrating an example wireless network,according to some embodiments;

FIG. 5 illustrates an example configuration of carrier aggregation withSRS carrier-based switching, according to some embodiments;

FIG. 6 is a flow diagram illustrating an example method in a UE,according to particular embodiments;

FIG. 7 is a flow diagram illustrating an example method in a networknode, according to some embodiments;

FIG. 8A is a block diagram illustrating an example embodiment of awireless device;

FIG. 8B is a block diagram illustrating example components of a wirelessdevice;

FIG. 9A is a block diagram illustrating an example embodiment of anetwork node; and

FIG. 9B is a block diagram illustrating example components of a networknode.

DETAILED DESCRIPTION

Third Generation Partnership Project (3GPP) long term evolution (LTE)wireless networks may use sounding reference signals (SRS). SRS areknown signals that are transmitted by a user equipment (UE) so that aneNodeB can estimate different uplink-channel properties. The estimatesmay be used for uplink scheduling, link adaptation, and also fordownlink multiple antenna transmission, particularly for time divisionduplex (TDD) networks where the uplink and downlink use the samefrequencies.

LTE networks may support carrier aggregation (CA). Many networks maycarry traffic that is downlink-heavy, which results in a greater numberof aggregated downlink component carriers (CC) than the number of(aggregated) uplink CCs.

For the carrier supporting both uplink and downlink, transmit diversitybased feedback without precoding matrix indicator (PMI) and with SRS isbeneficial because channel reciprocity can be used. However, a UEgenerally has the capability of aggregating a larger number of downlinkcarriers than uplink carriers. As a result, some of the TDD carrierswith downlink transmission for the UE will not have an uplinktransmission that includes SRS. Channel reciprocity cannot be used forthese carriers. Carrier switching between TDD uplink carriers can be asolution to allow SRS transmission on these TDD carriers.

SRS based carrier switching supports SRS switching to and between TDDcomponent carrier(s). SRS based carrier switching is used where thecomponent carriers available for SRS transmission correspond to thecomponent carriers available for carrier aggregation of physicaldownlink shared channel (PDSCH), while the UE has fewer componentcarriers available for carrier aggregation of physical uplink sharedchannel (PUSCH).

3GPP defines absolute and relative power tolerance to control the uplinktransmit power quality. TS 36.101 also specifies transmit power controltolerance (absolute, relative, and aggregate) with CA, in a similar wayas described for non-CA above.

Particular problems exist with SRS carrier-based switching. Usingcurrent uplink power accuracy requirements, the SRS transmission may notobtain the power control accuracy when SRS carrier-based switching isused. This depends on the transmission gap in time between two uplinktransmissions in any carrier. If the transmission gap is larger than acertain value, then the UE has to meet absolute tolerance requirementfor uplink power control. Otherwise, the UE has to meet relativetolerance requirement for the uplink power control.

For SRS carrier-based switching, this can be a problem, because (1)there may not be any uplink transmission in the carrier within the gaptime; and (2) there may be a number of SRS carrier-based switchingoperations planned which may increase the gap time. In addition, uplinkand/or downlink LBT will also increase the gap when uplink and/ordownlink LBT is required in at least one carrier where SRS carrier-basedswitching is performed.

Particular embodiments obviate the problems described above and includea UE capable of performing the following steps. At step 1, the UE adaptsat least one parameter related to uplink transmit power control inresponse to SRS carrier-based switching for at least one carrier. Atstep 2, the UE configures itself to transmit signals in uplink based onthe adapted parameter, while meeting at least one predetermined uplinkpower control requirement. At step 3, the UE may save the at least oneparameter for using it later (e.g., at a next SRS switching hop or at anext SRS switching occasion to the same carrier). At step 4, the UE maytransmit signals in uplink based on the adapted parameter and/or performuplink power control based on the adapted parameter. Particular stepsmay be omitted in some embodiments.

In some embodiments, a network node performs the following steps. Atstep 1, the network node determines at least one parameter related touplink transmit power control to account for SRS carrier-based switchingin at least one carrier. At step 2, the network node transmits at leastone parameter (e.g., PC command, PC step size configuration, etc.)related to uplink power control to a UE based on at least one determinedparameter in step 1. At step 3, the network node saves the at least onedetermined parameter for using it later for one or more UEs (e.g., at anext SRS switching hop or at a next SRS switching occasion to the samecarrier). At step 4 the network node schedules the UE for transmittinguplink signals based on at least one determined parameter in step 1.Particular steps may be omitted in some embodiments.

Particular embodiments may enhance uplink power control performance whenSRS carrier-based switching is performed. The UE behavior for uplinkpower control under SRS switching is well defined. This enables thenetwork to configure the UE with uplink signals that the UE can transmitwith optimal power. Particular embodiments include flexibility to obtainuplink power control accuracy requirements when SRS carrier-basedswitching is used for both licensed and unlicensed spectrum. Someembodiments provide adaptation possibilities to SRS transmissions fordifferent carriers when SRS carrier-based switching is used involvinglicensed spectrum or unlicensed spectrum or both.

The following description sets forth numerous specific details. It isunderstood, however, that embodiments may be practiced without thesespecific details. In other instances, well-known circuits, structuresand techniques have not been shown in detail in order not to obscure theunderstanding of this description. Those of ordinary skill in the art,with the included descriptions, will be able to implement appropriatefunctionality without undue experimentation.

References in the specification to “one embodiment,” “an embodiment,”“an example embodiment,” etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to implement such feature, structure, orcharacteristic in connection with other embodiments, whether or notexplicitly described. These embodiments are presented as teachingexamples and are not to be construed as limiting the scope of thedisclosed subject matter. For example, certain details of the describedembodiments may be modified, omitted, or expanded upon without departingfrom the scope of the described subject matter.

Even though the examples herein are given in the license assisted access(LAA) context, the embodiments described herein are not limited to LAA.The described embodiments are not limited to LTE either, but can beadapted in other RATs too, e.g., UTRA, LTE-Advanced, SG, NX, NB-IoT,WiFi, BlueTooth, etc.

Particular embodiments are described with reference to FIGS. 4-9B of thedrawings, like numerals being used for like and corresponding parts ofthe various drawings. LTE is used throughout this disclosure as anexample cellular system, but the ideas presented herein may apply toother wireless communication systems as well.

FIG. 4 is a block diagram illustrating an example wireless network,according to a particular embodiment. Wireless network 100 includes oneor more wireless devices 110 (such as mobile phones, smart phones,laptop computers, tablet computers, MTC devices, or any other devicesthat can provide wireless communication) and a plurality of networknodes 120 (such as base stations or eNodeBs). Wireless device 110 mayalso be referred to as a UE. Network node 120 serves coverage area 115(also referred to as cell 115).

Some embodiments may use a non-limiting term user equipment (UE). The UEmay refer to any type of wireless device 110 capable of communicatingwith a network node 120 or another wireless device 110 over radiosignals, such as wireless signals 130. The UE may include a radiocommunication device, target device, device to device (D2D) UE, machinetype UE or UE capable of machine to machine communication (M2M), asensor equipped with UE, iPAD, Tablet, mobile terminals, smart phone,laptop embedded equipped (LEE), laptop mounted equipment (LME), USBdongles, Customer Premises Equipment (CPE), etc.

In some embodiments, generic terminology such as “radio network node” orsimply “network node (NW node)” is used. It may refer to any kind ofnetwork node such as a base station, radio base station, basetransceiver station, base station controller, network controller,evolved Node B (eNB), Node B, Multi-cell/multicast Coordination Entity(MCE), relay node, access point, radio access point, Remote Radio Unit(RRU) Remote Radio Head (RRH), a core network node (e.g., TCE, MME, MDTnode, MBMS node), or even an external node (e.g., 3rd party node, a nodeexternal to the current network), etc. The term “radio node” as usedherein may refer to a wireless device 110 or a network node 120.

In general, wireless devices 110 that are within coverage of networknode 120 (e.g., within cell 115 served by network node 120) communicatewith network node 120 by transmitting and receiving wireless signals130. For example, wireless devices 110 and network node 120 maycommunicate wireless signals 130 containing voice traffic, data traffic,and/or control signals. A network node 120 communicating voice traffic,data traffic, and/or control signals to wireless device 110 may bereferred to as a serving network node 120 for the wireless device 110.Communication between wireless device 110 and network node 120 may bereferred to as cellular communication. Wireless signals 130 may includeboth downlink transmissions (from network node 120 to wireless devices110) and uplink transmissions (from wireless devices 110 to network node120).

Each network node 120 may have a single transmitter or multipletransmitters for transmitting signals 130 to wireless devices 110. Insome embodiments, network node 120 may comprise a multi-inputmulti-output (MIMO) system. Similarly, each wireless device 110 may havea single receiver or multiple receivers for receiving signals 130 fromnetwork nodes 120 or other wireless devices 110.

Particular embodiments may include single carrier, multicarrier orcarrier aggregation (CA) operation. In carrier aggregation, the wirelessdevice (e.g., wireless device 110) is able to receive and/or transmitdata to more than one serving cell (e.g., cells 115 a and 115 b).Carrier aggregation may also be referred to as “multi-carrier system”,“multi-cell operation”, “multi-carrier operation”, “multi-carrier”transmission and/or reception. In CA one of the component carriers (CCs)is the primary component carrier (PCC) or simply primary carrier or evenanchor carrier. The remaining ones are called secondary componentcarrier (SCC) or simply secondary carriers or even supplementarycarriers. The serving cell may also be referred to as primary cell(PCell) or primary serving cell (PSC). Similarly, the secondary servingcell may be referred to as secondary cell (SCell) or secondary servingcell (SSC).

In Dual Connectivity (DC) operation, a UE (e.g., wireless device 110)can be served by at least two network nodes (e.g., network nodes 120)referred to as master eNB (MeNB) and secondary eNB (SeNB). Generally, inmultiple connectivity operation the UE can be served by two or morenodes (e.g., MeNB, SeNB1, SeNB2 and so on). The UE is configured withPCC from both MeNB and SeNB. The PCell from MeNB and SeNB are referredto as PCell and PSCell, respectively.

The PCell and PSCell operate the UE typically independently. The UE isalso configured with one or more SCCs from each of MeNB and SeNB. Thecorresponding secondary serving cells served by MeNB and SeNB arereferred to as SCell. The UE in DC typically has separate TX/RX for eachof the connections with MeNB and SeNB. This enables the MeNB and SeNB toindependently configure the UE with one or more procedures (e.g., radiolink monitoring (RLM), DRX cycle, etc.) on their PCell and PSCellrespectively. The methods and embodiments described herein areapplicable to both CA, DC and Multi-Connectivity (MC).

The term “signaling” used herein may comprise any of: high-layersignaling (e.g., via RRC), lower-layer signaling (e.g., via a physicalcontrol channel or a broadcast channel), or a combination thereof. Thesignaling may be implicit or explicit. The signaling may further beunicast, multicast or broadcast. The signaling may also be directly toanother node or via a third node.

The term DRS or discover (or discovery) signal may comprise of any typeof reference signal, which can be used by the UE for performing one ormore measurements. Examples of DRS are CRS, CSI-RS, PSS, SSS, MBSFN RS,etc. One or more DRS may be transmitted in the same DRS time resource.Examples of DRS time resource are symbol, subframe, slot, etc.

The term “measurement” herein refers to radio measurements. Someexamples of the radio measurements are: RSSI measurement, channeloccupancy measurement, WiFi RSSI measurement, signal strength or signalpower measurements (e.g., RSRP or CSI-RSRP), signal quality measurements(e.g., RSRQ, SINR), timing measurements (e.g., Rx-Tx, RSTD, RTT, TOA),radio link monitoring measurements (RLM), CSI, PMI, cell detection, cellidentification, number of successful reports, number of ACKs/NACKs,failure rate, error rate, etc. The measurements may be absolute orrelative (e.g., absolute RSRP and relative RSRP). The measurements maybe performed for one or more different purpose, e.g., RRM, SON,positioning, MDT, etc. The measurements may be, e.g., intra-frequencymeasurements, inter-frequency measurements, or CA measurements. Themeasurements may be performed in the licensed and/or unlicensedspectrum.

The term LBT used herein may correspond to any type of CSMA procedure ormechanism which is performed by the node on a carrier before deciding totransmit signals on that carrier. CSMA or LBT may also interchangeablybe referred to as clear channel assessment, clear channel determination,etc.

Wireless signals 130 may include SRS, such as those described withrespect to FIGS. 1 and 2. Wireless device 110 may perform power controlin the uplink. Wireless device 110 is operable to transmit a SRS on aplurality of carriers. Wireless device 110 may obtain an indication toperform SRS carrier-based switching for at least one carrier of theplurality of carriers. Wireless device 110 may adapt at least oneparameter for uplink transmit power control in response to the obtainedindication. Wireless device 110 may transmit an uplink signal using theadapted at least one parameter for uplink power control while meeting atleast one predetermined uplink power control requirement.

In particular embodiments, adapting the at least one parameter foruplink transmit power control comprises adapting a transmission gapparameter. Meeting at least one predetermined uplink power controlrequirement comprises meeting at least one absolute power controlrequirement or meeting at least one relative power control requirementbased on the transmission gap parameter. For example, wireless device110 may adapt the transmission gap parameter to 40 ms. Wireless device110 may meet at least one uplink power control requirement by meeting atleast one absolute power control requirement when the transmission gaplength is greater than 40 ms and meeting at least one relative powercontrol requirement when the transmission gap length is less than orequal to 40 ms.

In particular embodiments, wireless device 110 may obtain an indicationthat a listen-before-talk (LBT) procedure is used in the uplink ordownlink. Wireless device 110 may adapt at least one parameter foruplink transmit power control based on the indication that the LBTprocedure is used in the uplink or downlink. The indication that a LBTprocedure is used in the uplink or downlink may apply to a particularcarrier of the plurality of carriers. Adapting the at least oneparameter for uplink transmit power control may be based on whether thecarrier for SRS carrier-based switching is the same carrier as theindicated particular LBT carrier.

Network node 120 is operable to receive a SRS on a plurality ofcarriers. Network node 120 may send, to wireless device 110, anindication to perform SRS carrier-based switching for at least onecarrier of the plurality of carriers. Network node 120 may receive, fromwireless device 110, an uplink signal based on at least one parameterfor uplink transmit power control adapted in response to the sentindication, wherein the uplink signal meets at least one uplink powercontrol requirement.

In wireless network 100, each network node 120 may use any suitableradio access technology, such as long term evolution (LTE),LTE-Advanced, UMTS, HSPA, GSM, cdma2000, NR, WiMax, WiFi, and/or othersuitable radio access technology. Wireless network 100 may include anysuitable combination of one or more radio access technologies. Forpurposes of example, various embodiments may be described within thecontext of certain radio access technologies. However, the scope of thedisclosure is not limited to the examples and other embodiments coulduse different radio access technologies.

As described above, embodiments of a wireless network may include one ormore wireless devices and one or more different types of radio networknodes capable of communicating with the wireless devices. The networkmay also include any additional elements suitable to supportcommunication between wireless devices or between a wireless device andanother communication device (such as a landline telephone). A wirelessdevice may include any suitable combination of hardware and/or software.For example, in particular embodiments, a wireless device, such aswireless device 110, may include the components described with respectto FIG. 8A below. Similarly, a network node may include any suitablecombination of hardware and/or software. For example, in particularembodiments, a network node, such as network node 120, may include thecomponents described with respect to FIG. 9A below.

In general, a UE (such as wireless device 110) is served by a firstnetwork node (such as network node 120 a) with a PCell operating on afirst carrier frequency (f1), and the UE is also capable of being servedby at least one secondary serving cell (SCell) (such as network node 120b) also known as a first SCell.

The UE may further be capable of being served by two or more SCells: thefirst SCell and a second SCell and as follows. The first SCell operateson a second carrier frequency (f2) and the second SCell operates on athird carrier frequency (f3). The same applies for more than two SCells.As an example, the carrier f1 and f3 belong to a licensed spectrum orband, whereas f2 belongs to an unlicensed spectrum or frequency band.Other combinations are also possible.

In an unlicensed spectrum or band, contention based transmission isallowed (i.e., two or more devices (UE or network nodes) can access eventhe same part of spectrum based on certain fairness constraints, e.g.LBT). In this case no operator (or user or transmitter) owns thespectrum. In a licensed spectrum or licensed band, only contention freetransmission is allowed (i.e., only devices (UE or network nodes)allowed by the owner of the spectrum license can access the licensedspectrum).

In some embodiments, the UE may also be capable of being served by morethan two SCells (e.g., a third SCell operating on carrier frequency (f4)and so on). Frequency f4 can be either in a licensed spectrum (or band),or in unlicensed spectrum (or band). The carrier f1 is interchangeablyreferred to as PCC, while carriers f2, f3, and f4 may interchangeably bereferred to as SCC1, SCC2, and SCC3, respectively. An example isillustrated in FIG. 5.

FIG. 5 illustrates an example carrier aggregation configuration,according to some embodiments. The illustrated example includes atypical arrangement with five downlink component carriers and two uplinkcomponent carriers. The Pcell uses component carrier 52. The Scells usecomponent carriers 54 a, 54 b, 54 c, and 54 d.

One uplink is fixed in the Pcell component carrier 52. SRS switching isperformed on one of the SCells component carriers 54. At any point oftime, the configuration is a two uplink CA combination. The same examplescenario an also be shown with other numbers of aggregated CCs indownlink and uplink. The carriers, i.e. CCy, CCz, CCu and CCv, can be indifferent band also. For example, CCy can be in any band below 1 GHz,CCz can be in any band around 2 GHz, and CCu can be any band in 3.5 GHz.

The terms “served” or “being served” herein means that the UE isconfigured with the corresponding serving cell and can receive fromand/or transmit data to the network node on the serving cell (e.g., onPCell or any of the SCells). The data is transmitted or received viaphysical channels (e.g., PDSCH in downlink, PUSCH in uplink, etc.).

A network node may request a UE to switch SRS transmission to one ormore SCells as follows: (a) receiving a first SCell SRS switchingrequest message or command from a second network node for switching SRScarrier from the first SCell; (b) receiving a second SCell SRS switchingrequest message or command from a third network node for switching SRScarrier from the second SCell; and (c) receiving a third SCell SRSswitching request message or command from a fourth network node forswitching SRS carrier from the third SCell.

Particular embodiments are described for at least one SCell onunlicensed spectrum or in some cases for two SCells with one on licensedand one on unlicensed spectrum or frequency bands. However, theembodiments are applicable to any number of SCells where at least oneSCell operates on a component carrier belonging to an unlicensedspectrum or frequency band.

In some embodiments, at least some of the first, second, third, andfourth network nodes are the same or are co-located at the same site orlocation. For example, in such embodiments the UE may receive one ormore messages or command for switching SRS carrier(s) from one or moreSCells from the first network node. Also for example, in suchembodiments the UE may receive one or more messages for SRS switching ofone or more SCells from the PCell.

In some embodiments, any combination of the first, second, third andfourth network nodes are different and may be located at different sitesor location or may be logically different nodes that may still beco-located. In such embodiments, the UE may receive one or more messagesfor SRS carrier switching from one or more SCells from the respectiveSCells.

In some embodiments, one or more SRS switching messages or commands maybe received by the UE via RRC signaling. In some embodiments, one ormore SRS switching messages or command may be received by the UE via MACCE command.

Particular embodiments include methods in a UE of adapting uplinktransmissions when SRS carrier-based switching is used. In someembodiments, a UE is capable of performing the following steps. At step1, the UE adapts at least one parameter related to uplink transmit powercontrol in response to SRS carrier-based switching for at least onecarrier. At step 2, the UE configures itself to transmit signals inuplink based on the adapted parameter, while meeting at least onepredetermined uplink power control requirement. At step 3, the UE maysave the at least one parameter for using it later (e.g., at a next SRSswitching hop or at a next SRS switching occasion to the same carrier).At step 4, the UE may transmit signals in uplink based on the adaptedparameter and/or perform uplink power control based on the adaptedparameter. Particular steps may be omitted in some embodiments.

In particular embodiments, the power control (PC) may comprise thecontrolling of the total transmit power, average transmit power of oneor more carriers, total transmit power for one or more carriers,transmit power per carrier, transmit power for one or more uplinktransmissions (e.g., SRS transmission involved in SRS switching, anotherSRS transmission, PUCCH, PUSCH, etc.).

Example parameters include: transmission gap length, uplink powercontrol step (the amount of uplink power adjustment), uplink powercontrol step in time (the time between two uplink power settings in theUE), an uplink power control parameter in general, absolute transmitpower, relative transmit power, and a reference for determining SRStransmission power.

Example uplink power control requirements include: absolute transmitpower tolerance for non-CA case or for CA case; relative transmit powertolerance for non-CA case or for CA case; aggregate power controlrequirement for non-CA case or for CA case; uplink power controlaccuracy, any requirement related to output power dynamics, transmissionmask, minimum output power, transmit power setting accuracy in the UE,minimum or maximum transmit power adjustment in one step, minimum ormaximum transmit power adjustment over a number of steps or over acertain time, etc.

At step 1, the UE may adapt at least one parameter related to uplinktransmit power control in response to SRS carrier-based switching for atleast one carrier. The at least one parameter may comprise transmissiongap length. The transmission gap length herein refers to a time periodduring which the UE does not transmit any signal or the time between twoclosest UE transmissions. The UE may also turn off its transmitterpartly or fully. For example, in case of partial cessation of itstransmitter, the UE may turn off its RF front end but it may stilloperate its baseband processing unit. The inactivity may be due to lackof uplink traffic/data, inability to send uplink signals (e.g., due tolack of uplink grant/resources etc.), transmission avoidance to reduceor avoid uplink interference or emissions, etc.

The at least one parameter may be a power control parameter such asuplink power control step (the adjustment amount and/or the adjustmenttime periods).

The adaptation may be performed autonomously by the UE or may be basedon assistance received from a network node (e.g., eNodeB). Theadaptation may also be performed by the UE based on pre-defined rule.

The adaptation may be performed for one or more carrier frequencies. Ina further example, the adaptation may be performed for one or morecarrier frequencies with radio operation under a specific framestructure type (e.g., FS3).

In another embodiment, the adaptation may comprise determining theparameter as a function of SRS carrier-based switching configuration forat least one carrier. The parameter may depend on one or more of thefollowing SRS carrier-based switching configuration (R) aspects: (a)that SRS carrier-based switching can happen for at least one carrier(e.g., the parameter may be pre-defined and fixed but may be differentdepending on whether SRS carrier-based switching is performed or not);(b) the number of uplink carriers on which SRS carrier-based switchinghappens (e.g., the total number or the number of configured uplink SRStransmissions); (c) the time period (T1) during which the number of SRStransmissions has occurred; (d) the length of a single SRS switching;(e) SRS switching rate; (f) the length of a single SRS switching loop(e.g., involving all carriers no more than one time); (g) the maximum ora minimum length of SRS switching; (h) subframe type for SRStransmission (e.g., TDD special subframe or a normal uplink subframe);(i) the length of the SRS transmission occasion (e.g., 1 symbol or 3symbols); (j) the reference for determining the SRS transmission power(e.g., PUSCH of the same carrier or another reference signal/channel ora parameter); and (k) a characteristic (e.g., uplink or downlinkdirection, signal type, transmission power, etc.) for the transmissionpreceding the switched SRS transmission on the same carrier.

In a particular example, the UE adapts the transmission gap parameterassociated with uplink power control based on the comparison of the SRSswitching period (T1) with a threshold (H1). For example: if T1>H1, thenthe UE applies or assumes a first value (V1) of the transmission gapparameter associated with uplink power control; and if T1≤H1, then theUE applies a second value (V2) of the transmission gap parameterassociated with uplink power control.

An example of H1 is 20 ms. Examples of V1 and V2 are absolute accuracyand relative accuracy values of uplink power control step size,respectively.

In yet another aspect of this embodiment, the transmission gap parameterassociated with uplink power control to account for SRS carrier-basedswitching is determined by a function (TG). TG is typically expressed intime units or time resources (e.g., symbols, time slots, subframes,frames, X ms, Y seconds, etc.).

If the transmission gap is larger than TG, then the UE has to meetabsolute tolerance requirement for uplink power control, otherwise, theUE has to meet relative tolerance requirement for the uplink powercontrol. The absolute tolerance or accuracy of the uplink power controlstep size is less stringent than the relative tolerance or accuracy ofthe uplink power control step size. This rule requires the UE toregularly monitor and determine the expected gap length after theoccurrence of SRS transmission. Based on the determined gap length, theUE adjusts its transmitter circuitry to meet the corresponding uplinkpower control requirements.

An example of the function (TG) may be expressed by a general functionas follows:

TG=f(T0,Δs)  (1)

where T0 is a fixed minimum value or basic gap length (e.g., T0=20 ms).The symbol Δs is a duration of variable gap length in negative valuethat may be decided by the UE autonomously, which corresponds to theeffect of SRS carrier-based switching for at least one of the carriers.Δs can be one or more parameters defining SRS carrier-based switchingconfiguration. Examples of Δs are SRS switching rate, SRS switchingperiod (T1), etc. as listed in the previous description. Maximum Δs mayalso be pre-defined and/or configured at the UE by the network node.

Another example of the function (TG) may be expressed by another generalexpression as follows:

TG=T0−Δs  (2)

A specific example of the function TG is as follows:

TG=20 ms−Δs  (3)

Another example of the function (TG) may be expressed by another generalexpression as follows:

TG=MAX{T1,(T0−Δs)}  (3-1)

A related specific example of the function TG is as follows:

TG=MAX{20 ms,(T0−Δs)}  (3-2)

Assuming T1=25 ms, then based on (3-1) and (3-2), TG=25 ms.

The value of Δs can be defined in one of the following ways. For exampleΔs may be defined as number of time resources (e.g., subframes). As anexample, Δs<T0 and a non-zero number.

Δs can be carrier specific, which can be defined based on SRSconfigurations, SRS periodicity, etc. for which SRS switching is beingperformed. As an example Δs(f1)=5 ms and Δs(f2)=3 ms.

In one example, Δs is non-negative positive value (e.g., thetransmission gap length is reduced by Δs if at least one SRScarrier-based switching occurs in any carrier). Thus, (TG) may beexpressed by another general expression as follows:

TG=T0+Δs  (4)

A specific example of the function TG is as follows:

TG=20 ms+Δs  (5)

Another example of the function (TG) may be expressed by another generalexpression as follows:

TG=MAX{T1,(T0+Δs)}  (5-1)

A related specific example of the function TG is as follows:

TG=MAX{20 ms,(T0+Δs)}  (5-2)

A rule may be specified that due to large number of SRS carrierswitching requirements, the transmission gap length associated withuplink power control for one or more of the involved carriers to meetabsolute power tolerance may be extended or reduced by certainmargin(s). For example one or more of the following may be specifiedthat: (a) the absolute power tolerance is the ability of the UEtransmitter to set its initial output power to a specific value for thefirst sub-frame at the start of a contiguous transmission ornon-contiguous transmission with a transmission gap smaller than (20−Δs)ms; (b) the absolute power tolerance is the ability of the UEtransmitter to set its initial output power to a specific value for thefirst sub-frame at the start of a contiguous transmission ornon-contiguous transmission with a transmission gap smaller than MAX{20ms, (T0−Δs)} ms; (c) the absolute power tolerance is the ability of theUE transmitter to set its initial output power to a specific value forthe first sub-frame at the start of a contiguous transmission ornon-contiguous transmission with a transmission gap larger than (20+Δs)ms; (d) the absolute power tolerance is the ability of the UEtransmitter to set its initial output power to a specific value for thefirst sub-frame at the start of a contiguous transmission ornon-contiguous transmission with a transmission gap larger than MAX{20ms, (T0+Δs)} ms; (e) the absolute power tolerance is the ability of theUE transmitter to set its initial output power to a specific value forthe first sub-frame at the start of a contiguous transmission ornon-contiguous transmission with a transmission gap larger than 20+Δs+δms, where δ is in e.g. number of time resources (e.g., subframes)representing implementation margin; (f) the absolute power tolerance isthe ability of the UE transmitter to set its initial output power to aspecific value for the first sub-frame at the start of a contiguoustransmission or non-contiguous transmission with a transmission gaplarger than MAX{20 ms, (20+Δs+δ)} ms, where δ is in e.g. number of timeresources (e.g., subframes) representing implementation margin; and (g)the absolute power tolerance is the ability of the UE transmitter to setits initial output power to a specific value for the first sub-frame atthe start of a contiguous transmission or non-contiguous transmissionwith a transmission gap smaller than MAX{20 ms, (20−Δs+δ)} ms, where δis in e.g. number of time resources (e.g., subframes) representingimplementation margin.

At step 2, the UE is configured to switch SRS transmission in uplink inat least one of the carriers based on the adapted parameter, whilemeeting at least one predetermined uplink power control requirement.

Particular embodiments include methods in a network node of adaptinguplink transmissions when SRS carrier-based switching is used. Forexample, methods in a network node may include the following steps. Atstep 1, the network node determines at least one parameter related touplink transmit power control to account for SRS carrier-based switchingin at least one carrier. At step 2, the network node transmits at leastone parameter (e.g., PC command, PC step size configuration, etc.)related to uplink power control to a UE based on at least one determinedparameter from step 1. At step 3, the network node may save the at leastone determined parameter for using it later for one or more UEs (e.g.,at a next SRS switching hop or at a next SRS switching occasion to thesame carrier). At step 4, the network node may schedule the UE fortransmitting uplink signals based on at least one determined parameterfrom step 1. Particular embodiments may omit some steps.

The power control (PC) may be the total transmit power, transmit powerfor one or more carriers, transmit power for one or more uplinktransmissions (e.g., SRS transmission involved in SRS switching, anotherSRS transmission, PUCCH, PUSCH, etc.).

Example parameters include: transmission gap length, uplink powercontrol step (the amount of uplink power adjustment), uplink powercontrol step in time (the time between two uplink power settings in theUE), an uplink power control parameter in general, absolute transmitpower, relative transmit power, and a reference for determining SRStransmission power.

Example uplink power control requirements include: absolute transmitpower tolerance for non-CA case or for CA case; relative transmit powertolerance for non-CA case or for CA case; aggregate power controlrequirement for non-CA case or for CA case; uplink power controlaccuracy, any requirement related to output power dynamics, transmissionmask, minimum output power, transmit power setting accuracy in theuplink, minimum or maximum transmit power adjustment in one step,minimum or maximum transmit power adjustment over a number of steps orover a certain time, etc.

At step 1, the network node adapts at least one parameter related touplink transmit power control to account for SRS carrier-based switchingin at least one carrier. In one example, the at least one parameter maybe a transmission gap length. The transmission gap length herein refersto a time period during which the UE does not transmit any signal or thetime between two closest UE transmissions. The UE may also turn off itstransmitter partly or fully. For example, in case of partial cessationof its transmitter the UE may turn off its RF front end but it may stilloperate its baseband processing unit. The inactivity may be due to lackof uplink traffic/data, inability to send uplink signals (e.g., due tolack of uplink grant/resources, etc.), transmission avoidance to reduceor avoid uplink interference or emissions, etc.

The at least one parameter may be a power control parameter such as anuplink power control step (the adjustment amount and/or the adjustmenttime periods). For example, the step in time may be extended and/or theamount of uplink transmit power adjustment may be increased depending onthe number of carriers for which SRS carrier-based switching isperformed at the UE.

The adaptation methods may be similar to those described above for themethod in a UE. The adapted parameter may further be stored in thenetwork node. Prior to performing the adaptation for a UE, the networknode may also determine whether the SRS carrier-based switching for atleast one carrier can be performed by the UE (e.g., based on the UEcapability).

At step 2, the network node may perform uplink power control for atleast one UE based on the adapted parameter. For example, the networknode may signal to the UE the adapted parameter or one or more of itscomponents (e.g., Δs) or an uplink power control configuration based onthe adapted parameter.

The power control may be performed via unicast, multicast, or broadcastsignaling.

Particular embodiments include a method in a UE of adapting uplinktransmissions based on the type of spectrum when SRS carrier-basedswitching is used. For example, a method in a UE may include thefollowing steps. At step 1, the UE adapts at least one parameter relatedto uplink transmit power control in response to SRS carrier-basedswitching for at least one carrier and at least one of the carriersrequires uplink and/or downlink LBT. At step 2, the UE configures itselfto transmit in uplink based on the adapted parameter, while meeting atleast one predetermined uplink power control requirement. At step 3, theUE saves the at least one parameter for using it later (e.g., at a nextSRS switching hop or at a next SRS switching occasion to the samecarrier). Examples of power control, power control parameters, and powercontrol requirements are the same as those described above for the otherembodiments.

At step 1, the at least one parameter may comprise transmission gaplength. The transmission gap may include a gap occurring due to LBTfailure or due to a combination of LBT failure and inactivity.

The at least one parameter may comprise a power control parameter suchas uplink power control step (the adjustment amount and/or theadjustment time periods). For example, the step in time may be extendedand/or the amount of uplink transmit power adjustment may be increaseddepending on the uplink LBT result or LBT success probability or may bea function of LBT (e.g., the maximum number of LBT attempts or thenumber of attempts until the channel access is successful).

In one embodiment, the adaptation may comprise selectively using theparameter configuration, depending on uplink LBT and/or uplink LBT(e.g., a first parameter configuration is used in the case with nouplink LBT or downlink LBT, while a second parameter configuration isused in the case with uplink LBT and/or downlink LBT). The secondparameter configuration may be pre-defined, pre-configured, receivedfrom another node, obtained based on a pre-defined rule, read from thememory, or calculated.

In another embodiment, the adaptation may comprise determining theparameter as a function of uplink LBT and/or downlink LBT when SRScarrier-based switching is performed involving at least one carrierwhich requires LBT (e.g., the parameter may depend on one or more of:(a) any of the parameters and factors listed in the embodimentsdescribed above; (b) that uplink LBT can take place for at least onecarrier for which SRS carrier-based switching will be performed (e.g.,the parameter may be pre-defined and fixed but may be differentdepending on whether uplink LBT is used or not); (c) that downlink LBTcan take place for at least one carrier for which SRS carrier-basedswitching will be performed (e.g., the parameter may be pre-defined andfixed but may be different depending on whether downlink LBT is used);(d) the number of uplink LBTs for at least one carrier for which SRScarrier-based switching will be performed (e.g., the total number or thenumber of successful or the number of failed LBTs); (e) the number ofdownlink LBTs for at least one carrier for which SRS carrier-basedswitching will be performed (e.g., the total number or the number ofsuccessful or the number of failed LBTs); (f) the time period duringwhich the number of uplink LBTs has occurred for at least one carrierfor which SRS carrier-based switching will be performed; (g) the timeperiod during which the number of downlink LBTs has occurred for atleast one carrier for which SRS carrier-based switching will beperformed; (h) the length of a single uplink LBT for at least onecarrier for which SRS carrier-based switching will be performed; (i) thelength of a single downlink LBT for at least one carrier for which SRScarrier-based switching will be performed; (i) the maximum or a minimumlength of uplink LBTs for at least one carrier for which SRScarrier-based switching will be performed; and (j) the maximum or aminimum length of downlink LBTs for at least one carrier for which SRScarrier-based switching will be performed.

The transmission gap parameter associated with uplink power control toaccount for uplink LBT and/or downlink LBT when SRS carrier-basedswitching is performed involving at least carrier which requires LBT maybe determined by a function (TG). An example of the function (TG) may beexpressed by a general function as follows:

TG=f(T0,Δs,Δ1,Δ2)  (6)

where T0 is a fixed minimum value or basic gap length (e.g., T0=20 ms).The symbol Δs is a duration of variable gap length in negative valuethat may be decided by the UE autonomously, which corresponds to theeffect of SRS carrier-based switching for at least one of the carriers.Δs can be one or more parameters defining SRS carrier-based switchingconfiguration. Examples of Δs are SRS switching rate, SRS switchingperiod (T1), etc. as listed in the previous embodiments. Maximum Δs mayalso be pre-defined and/or configured at the UE by the network node. Δ1and Δ2 are duration of variable gap lengths and may depend on uplink LBTand downlink LBT, respectively. Maximum values of Δ1 and Δ2 may bepre-defined and/or configured at the UE by the network node.

For example, Δ1 may be defined as number of time resources (e.g.,subframes) during which a UE does not transmit any signal in a cell(e.g., serving cell) due to LBT failure in uplink on that cell. As anexample, Δ1=8 ms. Δ2 may be defined as a number of time resources (e.g.,subframes) during which the UE does not receive any signal in a cell(e.g., serving cell) from another node (e.g., serving network node) dueto LBT failure in downlink on that cell. As an example, Δ2=8 ms.

As another example, a maximum limit on the aggregated value of Δ1 and Δ2can be pre-defined or configured by the network node. For example,(Δ1+Δ2)≤Δmax, where Δmax=20 ms.

Another example of the function (TG) may be expressed by another generalexpression is as follows:

TG=T0−Δs+Δ1+Δ2  (7)

A specific example of the function TG is as follows:

TG=20 ms−Δs+Δ1+Δ2  (8)

The value of Δs can be defined in one of the following ways. Forexample, Δs may be defined as number of time resources (e.g.,subframes). As a particular example, Δs<T0 and a non-zero number.

Δs can be carrier specific, which can be defined based SRSconfigurations, SRS periodicity, etc. for which SRS switching is beingperformed. As a particular example Δs(f1)=5 ms and Δs(f2)=3 ms.

Another example of the function (TG) may be expressed by another generalexpression as follows:

TG=MAX{T1,(T0−Δs+Δ1+Δ2)}  (8-1)

where the time period T1 is the duration in which the number of SRStransmissions have occurred.

Another example of the function (TG) may be expressed by another generalexpression as follows:

TG=MAX{T1,(T0+Δs+Δ1+Δ2)}  (8-1)

In one example, Δ1 and Δ2 are non-negative positive values (e.g., thetransmission gap length is extended with Δ1 if at least one uplink LBToccurs or if uplink LBT fails at least once. In another example, Δ1and/or Δ2 may be negative (e.g., if downlink LBT is detected by the UE,the transmission gap may be shortened). Parameters Δ1 and/or Δ2 may bedetermined by the UE or may be received from a network node.

Another specific example of the function TG, assuming there is no LBT indownlink or LBT in downlink is successful during certain number ofsubframes, is as follows:

TG=20 ms−Δs+Δ1  (9)

Another specific example of the function TG, assuming there is no LBT inuplink or LBT in uplink is successful during certain number ofsubframes, is as follows:

TG=20 ms−Δs+Δ2  (10)

In one example, Δs is non-negative positive value (e.g., thetransmission gap length is reduced by Δs if at least one SRScarrier-based switching occurs in any carrier). Thus, (TG) may beexpressed by another general expression as follows:

TG=T0+Δs+Δ1+Δ2  (11)

A specific example of the function TG is as follows:

TG=20 ms+Δs+Δ1+Δ2  (12)

Another specific example of the function TG, assuming there is no LBT indownlink or LBT in downlink is successful during certain number ofsubframes, is as follows:

TG=20 ms+Δs+Δ1  (13)

Another specific example of the function TG, assuming there is no LBT inuplink or LBT in uplink is successful during certain number ofsubframes, is as follows:

TG=20 ms+Δs+Δ2  (14)

A rule may be specified that due to large number of SRS carrierswitching requirements in addition to due to LBT failure in uplinkand/or downlink, the transmission gap length associated with uplinkpower control to meet absolute power tolerance may be extended bycertain margins. For example one or more of the following may bespecified that: (a) the absolute power tolerance is the ability of theUE transmitter to set its initial output power to a specific value forthe first sub-frame at the start of a contiguous transmission ornon-contiguous transmission with a transmission gap larger than20+Δs+Δ1+Δ2 ms; (b) the absolute power tolerance is the ability of theUE transmitter to set its initial output power to a specific value forthe first sub-frame at the start of a contiguous transmission ornon-contiguous transmission with a transmission gap larger than20+Δs+Δ1+δ ms, where δ is in, for example, a number of time resources(e.g., subframes) representing implementation margin; (c) the absolutepower tolerance is the ability of the UE transmitter to set its initialoutput power to a specific value for the first sub-frame at the start ofa contiguous transmission or non-contiguous transmission with atransmission gap larger than 20+Δs+Δ2+δ ms, where δ is in, for example,number of time resources (e.g., subframes) representing implementationmargin.

At step 2, the UE is configured to switch SRS transmission in uplink inat least one of the carriers based on the adapted parameter, whilemeeting at least one predetermined uplink power control requirement.Example uplink power requirements are described above.

Particular embodiments include methods in a network node of adaptinguplink transmissions based on type of spectrum when SRS carrier-basedswitching is used. For example, a method in a network node may comprisethe following steps. At step 1, the network node adapts at least oneparameter related to uplink transmit power control to account for atleast one of uplink LBT of a UE and downlink LBT when SRS carrier-basedswitching is performed for at least one carrier. At step 2, the networknode performs uplink power control for a UE based on the adaptedparameter. At step 3, the network node saves the at least one parameterfor using it later for one or more UEs (e.g., at a next SRS switchinghop or at a next SRS switching occasion to the same carrier). Particularembodiments may omit some steps.

The power control (PC) may be the total transmit power, transmit powerfor one or more carriers, transmit power for one or more uplinktransmissions (e.g., SRS transmission involved in SRS switching, anotherSRS transmission, PUCCH, PUSCH, etc.).

Example parameters include: transmission gap length, uplink powercontrol step (the amount of uplink power adjustment), uplink powercontrol step in time (the time between two uplink power settings in theUE), an uplink power control parameter in general, absolute transmitpower, relative transmit power, and a reference for determining SRStransmission power.

Example uplink power control requirements include: absolute transmitpower tolerance for non-CA case or for CA case; relative transmit powertolerance for non-CA case or for CA case; aggregate power controlrequirement for non-CA case or for CA case; UL power control accuracy,any requirement related to output power dynamics, transmission mask,minimum output power, transmit power setting accuracy in the UE, minimumor maximum transmit power adjustment in one step, minimum or maximumtransmit power adjustment over a number of steps or over a certain time,etc.

At step 1, the network node adapts at least one parameter related touplink transmit power control, to account for at least one of uplink LBTof a UE and downlink LBT when SRS carrier-based switching is used for atleast one carrier which requires LBT.

In one example, the at least one parameter may be a transmission gaplength. The transmission gap may include a gap occurring due to LBTfailure or due to combination of LBT failure and inactivity when SRScarrier-based switching is used involving at least one carrier whichrequires LBT.

The at least one parameter may be a power control parameter such as anuplink power control step (the adjustment amount and/or the adjustmenttime periods). For example, the step in time may be extended and/or theamount of uplink transmit power adjustment may be increased depending onthe uplink LBT result or a success probability or may be a function ofLBT when SRS carrier-based switching is used involving at least onecarrier which requires LBT (e.g., the maximum number of LBT attempts orthe number of attempts until the channel access is successful).

The adaptation methods are similar to those described in the embodimentsabove. In some embodiments, the adapted parameter may further be storedin the network node. Prior to performing the adaptation for a UE, thenetwork node may also determine whether the uplink LBT can be performedby the UE (e.g., based on the UE capability).

At step 2, the network node may perform uplink power control for a UEbased on the adapted parameter. For example, the network node may signalto the UE the adapted parameter or one or more of its components (e.g.,Δs and/or Δ1 and/or Δ2) or an uplink power control configuration basedon the adapted parameter.

The power control may be performed via unicast, multicast, or broadcastsignaling.

The examples described above may be generally represented by theflowcharts in FIG. 6 (with respect to a wireless device) and FIG. 7(with respect to a network node).

FIG. 6 is a flow diagram illustrating an example method in a UE,according to some embodiments. In particular embodiments, one or moresteps of FIG. 6 may be performed by wireless device 110 described withrespect to FIG. 4.

The method begins at step 612, where a UE obtains an indication toperform SRS carrier-based switching for at least one carrier of aplurality of carriers. For example wireless device 110 may be operatingin carrier aggregation using multiple component carriers. Wirelessdevice 110 may receive an indication from network node 120 to switch toa different component carrier for transmitting SRS (e.g., with respectto FIG. 5, switch from transmitting SRS on component carrier 54 a tocomponent carrier 54 b). In some embodiments, wireless device 110 mayreceive the indication via a MAC CE command.

At step 614, the UE adapts at least one parameter for uplink transmitpower control in response to the obtained indication. For example,wireless device 110 may adapt any of the power control parametersdescribed in the embodiments above.

As a particular example, the power control parameter may comprise atransmission gap. The transmission gap may normally be set to 20 ms.Wireless device 110 may adapt the parameter to 40 ms when performing SRScarrier-based switching.

At step 616, the UE transmits an uplink signal using the adapted atleast one parameter for uplink power control while meeting at least onepredetermined uplink power control requirement. For example, wirelessdevice 110 may transmit an uplink signal to meet any of the powercontrol requirements described in the embodiments above.

As a particular example, using the adapted transmission gap parameter of40 ms, the UE may meet absolute power control requirements when thetransmission gap length is greater than 40 ms and meet relative powercontrol requirements when the transmission gap length is less than orequal to 40 ms.

Modifications, additions, or omissions may be made to method 600.Additionally, one or more steps in method 600 of FIG. 6 may be performedin parallel or in any suitable order. The steps of method 600 may berepeated over time as necessary.

FIG. 7 is a flow diagram illustrating an example method in a networknode, according to some embodiments. In particular embodiments, one ormore steps of FIG. 7 may be performed by network node 120 described withrespect to FIG. 4.

The method begins at step 712, where a network node sends, to a UE, anindication to perform SRS carrier-based switching for at least onecarrier of the plurality of carriers. For example, network node 120 maysend an indication (e.g., a MAC CE command) to wireless device 110 forwireless device 110 to begin transmitting SRS on a different componentcarrier.

At step 714, the network node sends, to the UE, at least one parameterfor uplink transmit power control. For example, network node 120 maysend a new transmission gap parameter to wireless device 110.

In some embodiments, network node 120 may send a new transmission gapvalue of 40 ms. In other embodiments, network node 120 may sendtransmission gap as a parameter, and the UE is responsible fordetermining an adapted value for transmission gap.

Other embodiments may skip step 714. For example, the UE may bepreconfigured to use a transmission gap of 20 ms until receiving anindication to perform SRS carrier-based switching, at which time the UEis preconfigured to adapt the transmission gap to 40 ms.

At step 716, the network node receives, from the UE, an uplink signalbased on at least one parameter for uplink transmit power controladapted in response to the obtained indication and the uplink signalmeets at least one uplink power control requirement. For example,network node 120 may receive an uplink signal from wireless device 110according to the method described in FIG. 6, or any of the other exampleembodiments described above.

Modifications, additions, or omissions may be made to method 700.Additionally, one or more steps in method 700 of FIG. 7 may be performedin parallel or in any suitable order. The steps of method 700 may berepeated over time as necessary.

FIG. 8A is a block diagram illustrating an example embodiment of awireless device. The wireless device is an example of the wirelessdevices 110 illustrated in FIG. 4. In particular embodiments, thewireless device is capable of obtaining an indication to perform SRScarrier-based switching for at least one carrier of a plurality ofcarriers; adapting at least one parameter for uplink transmit powercontrol in response to the obtained indication; and transmitting anuplink signal using the adapted at least one parameter for uplink powercontrol while meeting at least one predetermined uplink power controlrequirement.

Particular examples of a wireless device include a mobile phone, a smartphone, a PDA (Personal Digital Assistant), a portable computer (e.g.,laptop, tablet), a sensor, a modem, a machine type (MTC) device/machineto machine (M2M) device, laptop embedded equipment (LEE), laptop mountedequipment (LME), USB dongles, a device-to-device capable device, avehicle-to-vehicle device, or any other device that can provide wirelesscommunication. The wireless device includes transceiver 810, processingcircuitry 820, memory 830, and power source 840. In some embodiments,transceiver 810 facilitates transmitting wireless signals to andreceiving wireless signals from wireless network node 120 (e.g., via anantenna), processing circuitry 820 executes instructions to provide someor all of the functionality described herein as provided by the wirelessdevice, and memory 830 stores the instructions executed by processingcircuitry 820. Power source 840 supplies electrical power to one or moreof the components of wireless device 110, such as transceiver 810,processing circuitry 820, and/or memory 830.

Processing circuitry 820 includes any suitable combination of hardwareand software implemented in one or more integrated circuits or modulesto execute instructions and manipulate data to perform some or all ofthe described functions of the wireless device. In some embodiments,processing circuitry 820 may include, for example, one or morecomputers, one more programmable logic devices, one or more centralprocessing units (CPUs), one or more microprocessors, one or moreapplications, and/or other logic, and/or any suitable combination of thepreceding. Processing circuitry 820 may include analog and/or digitalcircuitry configured to perform some or all of the described functionsof wireless device 110. For example, processing circuitry 820 mayinclude resistors, capacitors, inductors, transistors, diodes, and/orany other suitable circuit components.

Memory 830 is generally operable to store computer executable code anddata. Examples of memory 830 include computer memory (e.g., RandomAccess Memory (RAM) or Read Only Memory (ROM)), mass storage media(e.g., a hard disk), removable storage media (e.g., a Compact Disk (CD)or a Digital Video Disk (DVD)), and/or or any other volatile ornon-volatile, non-transitory computer-readable and/orcomputer-executable memory devices that store information.

Power source 840 is generally operable to supply electrical power to thecomponents of wireless device 110. Power source 840 may include anysuitable type of battery, such as lithium-ion, lithium-air, lithiumpolymer, nickel cadmium, nickel metal hydride, or any other suitabletype of battery for supplying power to a wireless device.

In particular embodiments, processing circuitry 820 in communicationwith transceiver 810 obtains an indication to perform SRS carrier-basedswitching for at least one carrier of a plurality of carriers; adapts atleast one parameter for uplink transmit power control in response to theobtained indication; and transmits an uplink signal using the adapted atleast one parameter for uplink power control while meeting at least onepredetermined uplink power control requirement.

Other embodiments of the wireless device may include additionalcomponents (beyond those shown in FIG. 8A) responsible for providingcertain aspects of the wireless device's functionality, including any ofthe functionality described above and/or any additional functionality(including any functionality necessary to support the solution describedabove).

FIG. 8B is a block diagram illustrating example components of a wirelessdevice 110. The components may include obtaining module 850, adaptingmodule 852, and transmitting module 854.

Obtaining module 850 may perform the obtaining functions of wirelessdevice 110. For example, obtaining module 850 may receive signaling fromnetwork node 120 indicating that wireless device 110 should perform SRScarrier-based switching. In certain embodiments, obtaining module 850may include or be included in processing circuitry 820. In particularembodiments, obtaining module 850 may communicate with adapting module852 and transmitting module 854.

Adapting module 852 may perform the adapting functions of wirelessdevice 110. For example, adapting module 852 may adapt a power controlparameter according to any of the examples and embodiments describedabove. In certain embodiments, adapting module 852 may include or beincluded in processing circuitry 820. In particular embodiments,adapting module 852 may communicate with obtaining module 850 andtransmitting module 854.

Transmitting module 854 may perform the transmitting functions ofwireless device 110. For example, transmitting module 854 may transmitan uplink signal to network node 120 while meeting power controlrequirements according to any of the examples or embodiments describedabove. In certain embodiments, transmitting module 854 may include or beincluded in processing circuitry 820. In particular embodiments,transmitting module 854 may communicate with obtaining module 850 andadapting module 852.

FIG. 9A is a block diagram illustrating an example embodiment of anetwork node. The network node is an example of the network node 120illustrated in FIG. 4. In particular embodiments, the network node iscapable of sending, to a wireless device, an indication to perform SRScarrier-based switching for at least one carrier of a plurality ofcarriers; and receiving, from the wireless device, an uplink signalbased on at least one parameter for uplink transmit power controladapted in response to the sent indication, wherein the uplink signalmeets at least one uplink power control requirement.

Network node 120 can be an eNodeB, a nodeB, a base station, a wirelessaccess point (e.g., a Wi-Fi access point), a low power node, a basetransceiver station (BTS), a transmission point or node, a remote RFunit (RRU), a remote radio head (RRH), or other radio access node. Thenetwork node includes at least one transceiver 910, at least oneprocessing circuitry 920, at least one memory 930, and at least onenetwork interface 940. Transceiver 910 facilitates transmitting wirelesssignals to and receiving wireless signals from a wireless device, suchas wireless devices 110 (e.g., via an antenna); processing circuitry 920executes instructions to provide some or all of the functionalitydescribed above as being provided by a network node 120; memory 930stores the instructions executed by processing circuitry 920; andnetwork interface 940 communicates signals to backend networkcomponents, such as a gateway, switch, router, Internet, Public SwitchedTelephone Network (PSTN), controller, and/or other network nodes 120.Processing circuitry 920 and memory 930 can be of the same types asdescribed with respect to processing circuitry 820 and memory 830 ofFIG. 8A above.

In some embodiments, network interface 940 is communicatively coupled toprocessing circuitry 920 and refers to any suitable device operable toreceive input for network node 120, send output from network node 120,perform suitable processing of the input or output or both, communicateto other devices, or any combination of the preceding. Network interface940 includes appropriate hardware (e.g., port, modem, network interfacecard, etc.) and software, including protocol conversion and dataprocessing capabilities, to communicate through a network.

In particular embodiments, processing circuitry 920 in communicationwith transceiver 910 sends an indication to perform SRS carrier-basedswitching for at least one carrier of a plurality of carriers; andreceives an uplink signal based on at least one parameter for uplinktransmit power control adapted in response to the sent indication,wherein the uplink signal meets at least one uplink power controlrequirement.

Other embodiments of network node 120 include additional components(beyond those shown in FIG. 9A) responsible for providing certainaspects of the network node's functionality, including any of thefunctionality described above and/or any additional functionality(including any functionality necessary to support the solution describedabove). The various different types of network nodes may includecomponents having the same physical hardware but configured (e.g., viaprogramming) to support different radio access technologies, or mayrepresent partly or entirely different physical components.

FIG. 9B is a block diagram illustrating example components of a networknode 120. The components may include sending module 950 and receivingmodule 952.

Sending module 950 may perform the sending functions of network node120. For example, sending module 950 may send an indication to wirelessdevice 110 to perform SRS carrier-based switching for at least onecarrier of a plurality of carriers. In certain embodiments, sendingmodule 950 may include or be included in processing circuitry 920. Inparticular embodiments, sending module 950 may communicate withreceiving module 952.

Receiving module 952 may perform the receiving functions of network node120. For example, receiving module 952 may receive an uplink signal fromwireless device 110. In certain embodiments, receiving module 952 mayinclude or be included in processing circuitry 920. In particularembodiments, receiving module 952 may communicate with sending module950.

Modifications, additions, or omissions may be made to the systems andapparatuses disclosed herein without departing from the scope of theinvention. The components of the systems and apparatuses may beintegrated or separated. Moreover, the operations of the systems andapparatuses may be performed by more, fewer, or other components.Additionally, operations of the systems and apparatuses may be performedusing any suitable logic comprising software, hardware, and/or otherlogic. As used in this document, “each” refers to each member of a setor each member of a subset of a set.

Modifications, additions, or omissions may be made to the methodsdisclosed herein without departing from the scope of the invention. Themethods may include more, fewer, or other steps. Additionally, steps maybe performed in any suitable order.

Although this disclosure has been described in terms of certainembodiments, alterations and permutations of the embodiments will beapparent to those skilled in the art. Accordingly, the above descriptionof the embodiments does not constrain this disclosure. Other changes,substitutions, and alterations are possible without departing from thespirit and scope of this disclosure, as defined by the claims below.

Abbreviations used in the preceding description include:

3GPP Third Generation Partnership Project

BTS Base Transceiver Station

CA Carrier Aggregation

CC Component Carrier

CCA Clear Channel Assessment

CW Contention Window

D2D Device to Device

DL Downlink

DRS Discovery Signal

eNB eNodeB

FDD Frequency Division Duplex

LAA License Assisted Access

LBT Listen-Before-Talk

LTE Long Term Evolution

MAC Medium Access Control

M2M Machine to Machine

MIMO Multi-Input Multi-Output

MTC Machine Type Communication

NR New Radio

PDSCH Physical Downlink Shared Channel

PUCCH Physical Uplink Control Channel

RAN Radio Access Network

RAT Radio Access Technology

RB Radio Bearer

RBS Radio Base Station

RNC Radio Network Controller

RRC Radio Resource Control

RRH Remote Radio Head

RRU Remote Radio Unit

RSRP Reference Symbol Received Power

RSRQ Reference Symbol Received Quality

SCell Secondary Cell

TDD Time Division Duplex

UE User Equipment

UL Uplink

UTRAN Universal Terrestrial Radio Access Network

WAN Wireless Access Network

1. A method for use in a user equipment (UE) operable to transmit asounding reference signal (SRS) on a plurality of carriers, the methodcomprising: obtaining an indication to perform SRS carrier-basedswitching for at least one carrier of the plurality of carriers;adapting at least one parameter for uplink transmit power control inresponse to the obtained indication; and transmitting an uplink signalusing the adapted at least one parameter for uplink power control whilemeeting at least one predetermined uplink power control requirement. 2.The method of claim 1, wherein: adapting the at least one parameter foruplink transmit power control comprises adapting a transmission gapparameter; and meeting at least one predetermined uplink power controlrequirement comprises meeting at least one absolute power controlrequirement or meeting at least one relative power control requirementbased on the transmission gap parameter.
 3. The method of claim 2,wherein: adapting the transmission gap parameter comprises adapting thetransmission gap parameter to 40 ms; and meeting at least onepredetermined uplink power control requirement comprises meeting atleast one absolute power control requirement when the transmission gaplength is greater than 40 ms and meeting at least one relative powercontrol requirement when the transmission gap length is less than orequal to 40 ms.
 4. The method of claim 1, wherein adapting thetransmission gap parameter comprises adapting at least one of an uplinkpower control step power value, an uplink power control step time value,an absolute transmit power, and a relative transmit power.
 5. The methodof claim 1, wherein meeting the at least one uplink power controlrequirement comprises meeting at least one of an absolute transmit powertolerance, an aggregate power control requirement, an uplink powercontrol accuracy requirement, and minimum or maximum transmit poweradjustment over a single step or period of time.
 6. The method of claim1, further comprising obtaining an indication that a listen-before-talk(LBT) procedure is used in an uplink or downlink; and wherein adaptingthe at least one parameter for uplink transmit power control is furtherbased on the indication that the LBT procedure is used in the uplink ordownlink.
 7. The method of claim 6, wherein: the indication that a LBTprocedure is used in the uplink or downlink applies to a particularcarrier of the plurality of carriers; and the adapting the at least oneparameter for uplink transmit power control is further based on whetherthe carrier for SRS carrier-based switching is the same carrier as theindicated particular LBT carrier.
 8. A method for use in a network nodeoperable to receive a sounding reference signal (SRS) on a plurality ofcarriers, the method comprising: sending, to a user equipment (UE), anindication to perform SRS carrier-based switching for at least onecarrier of the plurality of carriers; and receiving, from the UE, anuplink signal based on at least one parameter for uplink transmit powercontrol adapted in response to the sent indication, wherein the uplinksignal meets at least one uplink power control requirement.
 9. Themethod of claim 8, wherein: the at least one parameter for uplinktransmit power control adapted in response to the sent indicationcomprises a transmission gap parameter; and the at least one uplinkpower control requirement comprises meeting at least one absolute powercontrol requirement or meeting at least one relative power controlrequirement based on the transmission gap parameter.
 10. The method ofclaim 9, wherein: the at least one parameter for uplink transmit powercontrol adapted in response to the sent indication comprises atransmission gap parameter adapted to 40 ms; and the at least one uplinkpower control requirement comprises meeting at least one absolute powercontrol requirement when the transmission gap length is greater than 40ms and meeting at least one relative power control requirement when thetransmission gap length is less than or equal to 40 ms.
 11. The methodof claim 8, wherein the at least one parameter for uplink transmit powercontrol adapted in response to the sent indication comprises at leastone of an uplink power control step power value, an uplink power controlstep time value, an absolute transmit power, and a relative transmitpower.
 12. The method of claim 8, wherein the at least one uplink powercontrol requirement comprises meeting at least one of an absolutetransmit power tolerance, an aggregate power control requirement, anuplink power control accuracy requirement, and minimum or maximumtransmit power adjustment over a single step or period of time.
 13. Themethod of claim 8, further comprising sending, to the UE, the at leastone parameter for uplink transmit power control.
 14. The method of claim13, wherein the at least one parameter for uplink transmit power controlcomprises a transmission gap parameter.
 15. The method of claim 8,wherein the adapted at least one parameter for uplink transmit powercontrol is adapted based on whether a listen-before-talk (LBT) procedureis used in an uplink or downlink.
 16. A user equipment (UE) operable totransmit a sounding reference signal (SRS) on a plurality of carriers,the UE comprising a memory coupled to a processor, the processoroperable to: obtain an indication to perform SRS carrier-based switchingfor at least one carrier of the plurality of carriers; adapt at leastone parameter for uplink transmit power control in response to theobtained indication; and transmit an uplink signal using the adapted atleast one parameter for uplink power control while meeting at least onepredetermined uplink power control requirement.
 17. The UE of claim 16,wherein: the processor is operable to adapt the at least one parameterfor uplink transmit power control by adapting a transmission gapparameter; and meeting at least one predetermined uplink power controlrequirement comprises meeting at least one absolute power controlrequirement or meeting at least one relative power control requirementbased on the transmission gap parameter.
 18. The UE of claim 17,wherein: the processor is operable to adapt the transmission gapparameter to 40 ms; and meeting at least one predetermined uplink powercontrol requirement comprises meeting at least one absolute powercontrol requirement when the transmission gap length is greater than 40ms and meeting at least one relative power control requirement when thetransmission gap length is less than or equal to 40 ms.
 19. The UE ofclaim 16, wherein the processor is operable to adapt the transmissiongap parameter by adapting at least one of an uplink power control steppower value, an uplink power control step time value, an absolutetransmit power, and a relative transmit power.
 20. The UE of claim 16,wherein meeting the at least one uplink power control requirementcomprises meeting at least one of an absolute transmit power tolerance,an aggregate power control requirement, an uplink power control accuracyrequirement, and minimum or maximum transmit power adjustment over asingle step or period of time.